Recently, Orthogonal Frequency Division Multiplex (OFDM) has attracted much attention due to their capabilities of alleviating InterSymbol Interference (ISI) and improving a system capacity, and has a wide range of applications in Digital Video Broadcast (DVB) and Wireless Local Area Network (WLAN) fields.
OFDM is one of implementations of multicarrier transmission solutions. In a wideband wireless communication system, a wideband channel is converted into several parallel flat fading sub-channels through serial-to-parallel conversion, that is, a high-speed data stream is distributed to multiple subcarriers, so that a data symbol over each of the subcarriers has a relatively increased duration, and hence the system capacity can be effectively improved and the ISI caused by time dispersion of a wireless channel can be effectively alleviated; in addition, the data detection of each of the subcarriers can be simplified, and the impact of the frequency selective fading on the data transmission can be reduced. Further, with adding of a Cyclic Prefix (CP) to each data symbol, the Inter-channel Interference (ICI) caused by multipath can be effectively alleviated, so that the orthogonality between the subcarriers can be maintained.
However, no efficient error-correcting code is provided in the OFDM transmission, as a result, a transmission error occurring in the transmission cannot be corrected and the reliability of the transmission is lowered. An existing solution to overcome such a drawback is to combine the OFDM with the conventional channel coding. For example, a convolutional code or a Turbo code is employed to improve OFDM transmission reliability. With such a solution, although the transmission reliability is improved, the correcting capability is obtained by increasing system redundancy, so that the transmission efficiency is decreased.